This invention is directed generally to the field of cleaning apparatus or systems for contact lenses and more particularly to a novel and improved apparatus for effecting a post-cleaning rinsing of contact lenses by agitating the contact lenses in a rinsing solution.
Development of improved methods and apparatus for cleaning of contact lenses has assumed new importance with the advent of soft contact lenses and extended wear contact lenses. Both of these newer types of lenses are relatively porous as compared to the older "hard" lenses. Because these lenses are additionally intended for relatively longer periods of wear, thorough cleaning is necessary to remove residue which may have accumulated during wearing. In this regard, the relative porosity of these types of contact lenses tends to encourage collection and retention of proteinaceous and fatty body fluids. This results in a buildup of residues not only on the surfaces of the lenses but also within the pores thereof.
Moreover, such soft and extended wear contact lenses are generally hydrophilic, as well as porous, such that the proteinaceous and fatty materials or other contaminants tend to invade the porous matrix of the lenses. Frequently, an enzymatic cleaning solution of a generally available type is utilized for cleaning such lenses. The enzymes in such cleaning solutions tend to destroy or consume the proteinaceous and fatty substances which are present on the lenses. However, after subjecting the lenses to such an enzyme cleaning solution, they must be rinsed before placement on the eye. That is, since the enzyme solutions are hostile to body tissues, they would have an adverse effect if permitted to remain upon or within the porous lens after it is replaced on the eye.
Moreover, it should be recognized that enzyme cleaning procedures generally involve leaving the contact lenses in the enzyme solution for a period of six to twelve hours. Hence, there is often considerable penetration of the porous matrix of the lenses by the enzyme solution. Accordingly, it is important that the contact lenses be thoroughly rinsed to assure removal of any residual cleaning solution therefrom following the cleaning procedure. As mentioned above, such rinsing is necessary to assure that those materials which attack protein or potein-like substances will not remain on the lenses, and more particularly, within the pores thereof, when they are replaced on the eye.
The prior art has proposed utilizing a rotary unit to spin the lens in a rinsing solution-filled case, to effect such rinsing following enzyme cleaning. One such apparatus is shown in U.S. Pat. No. 3,623,492. However, the constant rotation of this type of device tends to cause more agitation of the rinsing solution at the periphery of the case than at the central portion thereof where the lens or lenses are disposed. This may result in insufficient agitation of the rinsing solution about the lenses themselves, as is necessary to effect thorough rinsing.
Accordingly, a problem has arisen in designing a container which will not only contain the lens or lenses but also provide sufficient open volume for proper agitation of the rinsing solution or water about lens or lenses. However, the solid lenses, when placed in this liquid solution or water tend to migrate to the areas of least agitation or net liquid flow within the container or case. Moreover, relatively thin, "soft" type lenses have a tendency to in effect "roll up" and migrate toward or even past through openings provided for liquid flow, to reach areas of minimum or no flow. It will be appreciated that such migration of the lenses defeats the purpose of agitation, resulting in possibly insufficient rinsing and penetration of the porous lens body to effect complete removal of the enzyme solution and their residues.
Moreover, the rotary device as proposed by the above prior art patent requires some form of seal where a rotary shaft or other rotation-imparting member passes through or into the solution-filled container. It will be appreciated that providing a reliable seal between relatively rotating parts always presents problems in design and fabrication. It is also known that rotating parts tend to experience wear while in service, necessitating periodic repair or replacement, or possibly leading to unsatisfactory operation or even failure. Additionally, the device shown in the above-referenced U.S. Pat. No. 3,623,492 is a manually operated device. Accordingly, there is some problem of possible user fatigue or simply of failure of the user to operate the device for a sufficient length of time or with sufficiently vigorous action to obtain the desired rinsing action.